Ports that set FETCH_CMD, FETCH_ENV, FETCH_BEFORE_ARGS, FETCH_AFTER_ARGS, or
have a do-fetch: target are now simply skipped in the output. A file whose
URLs are all "Not checked" (usually one that was just added or changed
before or during the last port survey run) is treated as though it was
not required to fetch for the port to be fetchable.

Sites running SecureIIS return 406 Not Acceptable to the HTTP HEAD
queries that the distfile survey does. If all your URLs are purple
with "406 Not Acceptable" repsonses, the site is likely running
SecureIIS.